The purpose of the Serum Markers and Rapid Triage Trial (SMART) is to evaluate the impact of serum markers of myocardial infarction on ED triage decision making when provided to "clinicians in real time" (within approximately 15 minutes) using the Biosite Diagnostics Triage Cardiac System. The Triage Cardiac System is a fluorescence immunoassay used for the quantitative determination of CK-MB, Tropin I and Myoglobin. Patients will be enrolled in this study who present to the Emergency Departments with symptoms suggestive of acute cardiac ischemia (ACI- including chest pain, shortness of breath, upper abdominal pain, syncope, dizziness) who have an ECG ordered by the attending physician as part of the ED evaluation for possible cardiac ischemia. While serum markers of myocardial infarction are part of the routine evaluation of patients with suspected ACI, these results are not routinely used in the ED triage decision process because the results may take 1-3 hours to return form the laboratory. All consenting adult patients who have a blood sample obtained for the measurement of cardiac markers as part of the evaluation of possible ACI in the ED will be randomized to have cardiac marker results determined using the Biosite system in the ED (as well as the central Laboratory) as compared to standard care (results determined in central laboratory) The Biosite system provides results with in approximately 15 minutes. This study will measure the impact of these results on the accuracy of ED triage and treatment decisions for patients with suspected ACI. It has been suggested that serum markers may improve ED triage decisions by quickly identifying patients with myocardial damage, particularly in those patients where patients where the initial ECG is either non-diagnostic or misread by the clinician. This hypothesis has not been prospectively tested. Admitted patients will receive standard care. Patients who have cardiac markers obtained in the ED who are discharged home will return for follow-up studies to exclude missed MI. All patients will complete a 30 day follow up telephone call. All patients (admitted and discharged) who have not reached a predetermined end point (MI, cardiac cath, diagnostic study to exclude ACI) will be asked to return to to the HAC Heart station to have a stress cardiac scan.